Main navigation

  • ICOET 2025
  • Registration
  • Lodging
  • Sponsors
  • Program
  • Presenters
  • About

The Influence of Fences and Fence Gaps on the Distribution of Wildlife Road Mortalities on a South Texas Highway

Breadcrumb

  • Home
  • ICOET 2019 Conference Program
  • The Influence of Fences and Fence Gaps on the Distribution of Wildlife Road Mortalities on a South Texas Highway
Thomas J. Yamashita. School of Earth Environmental and Marine Sciences, University of Texas Rio Grande Valley
Trinity D. Livingston. School of Earth Environmental and Marine Sciences, University of Texas Rio Grande Valley, Port Isabel, TX, 78578, USA
Kevin Ryer. School of Earth Environmental and Marine Sciences, University of Texas Rio Grande Valley, Port Isabel, TX, 78578, USA
John Young Jr. Environmental Affairs Division, Texas Department of Transportation, Austin, TX, 78701, USA
Richard J. Kline. School of Earth Environmental and Marine Sciences, University of Texas Rio Grande Valley, Port Isabel, TX, 78578, USA
Terrestrial Wildlife and Ecosystem Interactions with Transportation
Ocelots on the Brink

Roads are a major cause of mortality for many species, including the endangered ocelot (Leopardus pardalis) in South Texas. Between September 2016 and May 2018, the Texas Department of Transportation built 11.9 km of fencing and five wildlife crossing structures on State Highway 100 (SH100) near Brownsville, Texas. These structures are meant to keep wildlife, especially ocelots, out of the road area without sacrificing habitat connectivity. However, the fencing is broken by several gaps located at road intersections and private driveways. At driveways, wildlife guards were built to prevent wildlife from accessing the road way while at road intersections, wing walls were constructed. As part of a long-term monitoring program, a 15 km stretch of SH100 has been surveyed continuously since August 2015 for wildlife road mortalities encompassing the full fenced area and equal distances beyond each fence end. Using spatiotemporal statistics in ArcGIS and Python 3.7, we examined trends in wildlife road mortality hot spots before, during, and after construction to assess the impact of fencing on the spatial distribution of mortalities. Analyses using all mammals and herpetofauna have shown that mortalities have decreased but mortality hot spots have not changed, however this includes many species that would not be affected by fencing (small mammals and snakes). By excluding those species not affected by fencing, we can better assess the effectiveness of fencing and other mitigation structures at altering mortality spatial distribution. We expect that fencing will funnel wildlife towards fence ends and fence gaps creating new hot spots of wildlife road mortalities at those locations. This analysis will allow for a fine scale examination of changes in wildlife road mortality patterns following the construction of mitigation structures and assessment of factors that contribute to the rise of these hot spots.

Wildlife Road Mortality
Road mitigation structures
Hot spot analysis
ICOET 2025 — International Conference On Ecology and Transportation